In the European Telecommunication Standards Institute (ETSI) standard, resources forming an M2M network have unique resource identifiers (URIs). The URIs correspond to independent addresses allowing access to the respective resources. An addressing is a procedure of assigning the independent URIs to the respective resources and allowing access to the relevant resources through the URIs. Such URIs may be utilized as parameters of various supplementary operations associated with M2M resources.
The basic operation procedure for manipulating resources on the M2M network may include a resource create operation (“CREATE”), a resource retrieve operation (“RETRIEVE”), a resource update operation (“UPDATE”), and/or a resource delete operation (“DELETE”).
A basic idea to perform all resource manipulation and processing procedures, which have been executed in a single domain, is through a simple operation using URIs assigned to the respective resources. This might be structured with a RESTful architecture.
For example, in the case that a user retrieves a certain web page, the user may retrieve the web page using a URI corresponding to an address of a relevant web page. More specifically, as long as a user knows a URI corresponding to the web page to be retrieved, the user may easily send a request message for retrieving information contained in the web page, through a web browser. In this case, data of a web page structured according to a corresponding standard may be transmitted to user equipment. The received data may be displayed in a form of retrievable screen information in the user equipment.
Similarly, a single M2M device in an M2M network may include certain functions and information like a single web page described above. In the case that an unknown M2M device (i.e., an M2M device whose function and information are not known) is connected to an M2M network, it is necessary to know the function and information of the connected M2M device by performing a mutual communication using a message defined in a corresponding standard.
In the ETSI standard, a ‘discovery’ is defined as an operation (or function) which finds out the function and/or information of a certain M2M device by performing a mutual communication using standardized messages. The discovery corresponds to an operation of making a request from the outside (e.g., an M2M gateway, an application, etc.) to a specific M2M device. URI lists of all opened resources existing in the specific M2M device may obtained through the discovery operation. More specifically, a ‘discovery’ operation may make it possible to determine what structure a certain M2M device has, what information the M2M device generates, and how to investigate the inside of the M2M device. For example, in order to obtain information on web pages provided by a web server, it is necessary to retrieve a pre-defined web page file in a root directory of the web server. Like this, an entry point of an M2M device retrieval may be obtained through a ‘discovery’ operation.
Meanwhile, an M2M application may be created using M2M devices. In this case, some typical procedures may be required to be performed. First, it may be necessary to obtain access rights to a corresponding M2M device. Second, it may be necessary to check where a specific function or information of an M2M device can be obtained in a URI list associated with the M2M device. Herein, the second procedure may be omitted if an administrator clearly understands a device design architecture and URIs of resources prior to application development. However, in a case of accessing an unknown M2M device in order to obtain desired information on the unknown M2M device connected to an M2M network, resources (e.g., function or information) that can be provided by the unknown M2M device may be obtained in a URI form. In this case, a certain resource may be accessed by explicitly designating a corresponding URI in an obtained URI list. Third, it may be necessary to create a message requesting desired resources. For example, in the case that a request for obtaining specific information is sent in a hypertext transfer protocol (HTTP) message form, an HTTP GET message is sent to a corresponding URI obtained in a previous operation. In this case, various parameters (e.g., a filter or the like) may be included in a message body according to the typical standards (e.g., ETSI M2M standard, HTTP standard, etc.).
As described above, in order to access an M2M device on an M2M network, a message may be required to be directly sent to a corresponding URI in a RESTful message form (e.g., RESTful HTTP message form). However, such a typical method may have several problems or limitations as follows.
First, the message (e.g., HTTP message) corresponds to a protocol of a character string form and is defined by a strict format. Therefore, a developer has to configure an message according to a format required in various M2M devices. In this case, various errors may occur during the message configuration procedure.
Second, in an M2M network, a resource structure, a device connection state (e.g., connection of a new M2M device, removal of an existing M2M device, etc.), and/or an internal environment of an M2M device may be frequently changed. In this case, in order to continuously support an access to the M2M device, generating a new version of URI while maintaining a past URI may be required. However, in this case, with respect to functions of the M2M device to be provided and URIs corresponding to the functions, difficulties may occur in a device or resource management.